The major thrust of this study is to elucidate the basis of neoplastic transformation of normal tissues. Two experimental model systems were used in this project: (1) a rat hepatoma induced by the chemical carcinogen N,N-2,7-fluorenylene bis-2,2,2-trifluoroacetamide, which has been adapted to tissue culture (HTC cells); and (2) two intracisternal A particle (IAP) containing neoplasms, a plasma cell tumor (MOPC-104E) and differentiated neuroblastoma, also adapted to tissue culture (cell lines N-4, N-18, and NB-2A). Multidisciplinary approaches were required in this investigation. They involve tissue culture, biochemical and biophysical analyses, cytogenetics, immunology and tumor biology. Areas with special emphasis of research effort are: (1) extensive characterizations morphologically, biologically, biochemically and immunologically of KiMSV(RHHV), a transforming viral complex successfully rescued out of a co-culture of rat hepatoma tissue culture cells (HTC-H1) with K-NRK cells; (2) regulation of viral gene (GAG for gs antigens and ENV for envelope antigen) expressions; (3) the oncogenic potential of KiMSV(RHHV); (4) virus infection and the development of chromosome abnormalities during the process of neoplastic transformation, and (5) integrations of viral genome and its localization on host cell chromosome(s). BIBLIOGRAPHIC REFERENCES: Yang, S.S. and Wivel, N.A.: Physicochemical analysis of deoxyribonucleic acid product of murine intracisternal A particle RNA-dependent DNA polymerase. Biochem. et Biophys. Acta, 447:167-174, 1976. Yang, S.S., Malech, H.M., Wu, R.S. and Woronow, D.: Properties of a transforming virus, KiMSC(RHHV) isolated from a co-culture of rat HTC-H1 cells with K-NRK cells. J. Gen. Virol. (in press) 1977.